Could not cast or convert from System.String to System.Type

bug?
1

I am getting “System.ArgumentException: Could not cast or convert from System.String to System.Type.”. I have copied the error below.
I get it while I am enqueuing a job
BackgroundJob.Enqueue(() => _emailSender.SendEmail(“xxxxx”, 25, “xxxx”, “xxxx”, “xxxx”))

Any help on this is appreciated. Thank you very much!

{“FailedAt”:“2018-01-10T19:52:24.0855131Z”,“ExceptionType”:“Newtonsoft.Json.JsonSerializationException”,“ExceptionMessage”:“Error converting value “System.String, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e” to type ‘System.Type’. Path ‘[0]’, line 1, position 107.”,“ExceptionDetails”:“Newtonsoft.Json.JsonSerializationException: Error converting value “System.String, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e” to type ‘System.Type’. Path ‘[0]’, line 1, position 107. —> System.ArgumentException: Could not cast or convert from System.String to System.Type.\r\n at Newtonsoft.Json.Utilities.ConvertUtils.EnsureTypeAssignable(Object value, Type initialType, Type targetType)\r\n at Newtonsoft.Json.Utilities.ConvertUtils.ConvertOrCast(Object initialValue, CultureInfo culture, Type targetType)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType)\r\n — End of inner exception stack trace —\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateList(IList list, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)\r\n at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)\r\n at Hangfire.Common.JobHelper.FromJson[T](String value)\r\n at Hangfire.Storage.InvocationData.Deserialize()”}

2

I am getting error on System defined types. When I pass custom defined type, it works:

_backgroundJobClient.Enqueue(() => _emailSender.SendEmail(emailParams)); <- This works.
_backgroundJobClient.Enqueue(() => _emailSender.SendEmail(“string”)); <- This doesn’t work.

Any insights from expert on this is highly appreciated. Thank you!

3

Having same issue.
With hangfire latest version

4

We are also facing issues with this. Has anyone in this thread made any progress or reached any conclusions. We are using .net core 2.

This appears to happen in a non deterministic fashion. Some jobs fail many times with this error then pass.

One common theme is that all jobs initially fail with a transient error when making an http call. The subsequent retries that DO fail, fail with this error.

Error converting value "MarketingPreferences.Host.Events.Vortex.PrivacyServiceGetConsent, MarketingPreferences.Host, Version=1.8.3.0, Culture=neutral, PublicKeyToken=null" to type 'System.Type'. Path '[0]', line 1, position 149.

Newtonsoft.Json.JsonSerializationException: Error converting value "MarketingPreferences.Host.Events.Vortex.PrivacyServiceGetConsent, MarketingPreferences.Host, Version=1.8.3.0, Culture=neutral, PublicKeyToken=null" to type 'System.Type'. Path '[0]', line 1, position 149. ---> System.ArgumentException: Could not cast or convert from System.String to System.Type.
   at Newtonsoft.Json.Utilities.ConvertUtils.EnsureTypeAssignable(Object value, Type initialType, Type targetType)
   at Newtonsoft.Json.Utilities.ConvertUtils.ConvertOrCast(Object initialValue, CultureInfo culture, Type targetType)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType)
   --- End of inner exception stack trace ---
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateList(IList list, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)
   at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)
   at Hangfire.Common.JobHelper.FromJson[T](String value)
   at Hangfire.Storage.InvocationData.Deserialize()
5

I am also experiencing this issue. I have both client and server in the same solution. I have Cleaned the Solution and Rebuilt the solution, and still it intermittently fails as above: trying to convert the argument for the method being executed to System.Type. No solution at this stage.

1 Like
6

I had this issue to. I’m glad I found this post, this was driving me nuts. It appears if I use simple type (string) arguments to the delegate of the BackgoundJobClient.Enqueue() method, I get the “cannot convert string to type” error. If change my arguments to using a custom complex type, it works.

7

I haven’t had time to test this issue but has anyone tried an explicit cast:

_backgroundJobClient.Enqueue(() => _emailSender.SendEmail((string)“string”));

This might be a bug but I’d be interested to see if there is an easy workaround to it by playing with the casting.